Recently, since a large volume of information can be stored and random access is easy, various types of optical recording media such as CD-Rs, CD-RWs, MOs, are widely recognized and gains popularity as an external recording storage in an information processing apparatus such as computers. Among the various types of the optical recording media, optical recording media such as CD-Rs, DVD-Rs, and DVD+Rs having a recording layer containing organic dyes are relatively low in price, and have compatibility with a playback-only optical disc, thereby being popularly used in particular. For example, a typical CD-R, or the like, having recording layers containing organic dyes, has a dye-containing recording layer and a reflective layer on a transparent disc substrate in this order, and has a laminated structure having a protective layer to cover the recording layer and the reflective layer on which recording/reading are carried out by laser light through the substrate.
As one of means for further increasing the volume of storage capacity of these optical recording media, there can be included a medium that is provided with a plurality of recording layers, for example, a dual layer. In this case, from the viewpoint of convenience, the dual layer is required to be made in such a manner that recording/reading can be carried out from one side of the two recording layers. In order to respond to the requirement, the applicant of the present invention has been applied for a patent regarding an optical recording medium including a first recording layer containing a dye, a first translucent reflective layer, an intermediate resin layer, a second recording layer containing a dye, a second reflective layer, an adhesive layer, and a second substrate, on a first disk-shape transparent substrate, in this order (patent document 1). With this, recording information on the first recording layer and the second recording layer become possible from one side of the optical recording medium having two recording layers, and also, as the dual-layer type optical recording medium, reading signals from the one side becomes possible at the time of reading.
[Patent document 1] Japanese Laid-open Patent Application No. 2003-331463